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ESE Civil 2014 Paper 2: Official Paper

Option 2 : 0.88

CT 1: Ratio and Proportion

2672

10 Questions
16 Marks
30 Mins

**Concept:**

According to Lacey’s, the design formulas to build canal is as follows:

1) Silt factor ⇒ \(\rm{f = 1.76√ {{d_{mm}}}}\)

2) Velocity of flow ⇒ \(\rm{V = {\left[ {\frac{{Q{f^2}}}{{140}}} \right]^{\frac{1}{6}}}}\)

3) Hydraulic mean depth ⇒ \(\rm{R = \frac{{5{V^2}}}{{2f}}}\)

4) Wetted perimeter ⇒ \(\rm{P = 4.75√ Q}\)

5) Bed slope ⇒ \(\rm{S = \frac{{{f^{\frac{5}{3}}}}}{{3340 \times {Q^{\frac{1}{6}}}}}} \)

**Calculation:**

Given,

Median size of silt (d_{mm}) = 0.25 mm

Silt Factor is

∴ f = 1.76 √0.25 = **0.88**